Transporting and stacking sheet-like articles



March 3, 1964 F. UNGERER 3,123,354

TRANSPORTING AND STACKING SHEEP-LIKE ARTICLES Filed May 17, 1960 2 Sheets-Sheet 1 I Fig.2 54 4g 55 6249 47 63 INVENTOE Fritz UNGERER March 3, 1964 F. UNGERER 3,123,354

TRANSFORTING AND STACKING SHEET-LIKE ARTICLES Filed May 17, 1960 2 Sheets-Sheet 2 INVENTOE Fritz UNGERER United States Patent 3,123,354 TRANSPORTING AND STACKING SHEET-LIKE ARTICLES Fritz Ungerer, Arlingerstrasse 6, Pforzheim- Brotzingen, Germany Filed May 17, 1960, Ser. No. 29,610 Claims priority, application Switzerland Jan. 11, 1960 3 Claims. (Cl. 271-74) This invention relates to combination sheet transfer and stacking means for automatically transporting and thereafter stacking sheets at a predetermined location or station.

It is an object of this invention to provide means automatically transporting and then stacking or piling up sheets for forming an orderly stack thereof.

It is another object of this invention to provide means conducive to an efficient sheet stacking device for properly aligning at least one edge of each of a plurality of sheets in pile formation.

It is still a further object of this invention to provide means affording stacking of a plurality of sheets of various dimensions and different materials in predetermined fashion.

It is a further object of this invention to provide means envisioning a compact and efficacious sheet stacking device which permits quickly and in a simple manner stacking of sheets independently of their weight and thickness.

It is another important object of the present invention to provide means facilitating in a very accurate and positive manner transporting, transferring and stacking a plurality of sheets at a predetermined location, whereby the sheets are superimposed on each other with at least one edge of each thereof correctly aligned.

With these objects in view the stacking device according to the present invention comprises elongated movable transporting means having an upper face and a lower face, first means adjacent said upper face for retaining sheets supplied to said lower face and for releasing the sheets therefrom, second means being provided to operatively connect with the first means for influencing them to release the sheets from the lower face at a selected position or location. In this manner the sheets are stacked in superimposed relationship below said transporting means and adjacent the selected position to release said sheets successively from the transporting means for stacking purposes.

According to a further feature of the invention, the transporting means may be in the form of an endless conveyor belt, suction means being preferably provided to coact with a conveyor belt pervious to suction, to which belt the sheets are applied during displacement or movement to a predetermined location.

Further features of this invention and additional objects will become apparent from the detailed description given hereinafter. It should be understood however, that the detailed description and specific examples are set forth by way of illustration only and, while indicating preferred embodiments of the invention, are not given by way of limitation, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from the detailed disclosure.

For a more complete understanding of the present invention reference is had to the description and claims, taking into account the drawings, in which:

FIG. 1 is a side elevational View of the device of the present invention;

FIG. 2 is a fragmentary top plan view of a detail of the invention;

FIG. 3 is a fragmentary sectional view on an enlarged scale, taken along line 33 of FIG. 2;

3,123,354 Patented Mar. 3, 1964 ice FIG. 4 is a fragmentary plan view of a modified form of the detail shown in FIG. 2 and viewed from the underside thereof;

FIG. 5 is a sectional view taken along line 55 of FIG. 4;

FIG. 6 is a fragmentary View of a further modified form of the detail shown in FIG. 4;

FIG. 7 illustrates a modified embodiment of the detail shown in FIG. 3; and

FIG. 8 is a schematic view of the control devices of which only two are illustrated in FIG. 1.

Referring now more specifically to the drawings, roller 22 is mounted for rotation on support column 10, and roller 23 is mounted for rotation on column 11. Rollers 22, 23 support and drive an endless conveyor belt 24, which forms movable transporting means for the sheets to be stacked.

Conveyor belt 24 moves in a horizontal line between a first point of location 25 and a second location or station 26. Conveyor belt 24 has an upper face and a lower face 28.

An electric motor 34 drives roller 22 through drive belts 35.

Feeding means in the form of a conveyor 38 supply sheets 36 to the lower face 28 of conveyor belt 24 by moving each sheet 36 in the direction of arrow 37.

Orifice units are adapted to apply suction only, as marked by arrow 13, effective at lower face 28 of conveyor belt 24, and 42 are spaced across conveyor belt 24.

Adjacent units 4@, 41, 47, 48 and 49 provide alternate application of suction and pressure with respect to belt 24. They are valved for his purpose as indicated by arrows 14 pointing toward and away from lower belt face 28.

Orifice units 4t 41, 47, 48 and 49 are spaced across conveor belt 24 so that sheet 36 will be placed securely onto the lower face 28 of belt 24 and held thereon by a vacuum. Furthermore, belt 38 supplying successive sheets 36 overlaps location 25 of belt 24.

A platform 18, constituting sheet receiving means, is located below lower face 28 in the region of location 26. Platform 18 is vertically adjustable and has on its side a plurality of upright guide members with outwardly turned upper edges. Two such guide members are shown at 2%? and 21. An upright 19, extending upwardly further than upright guides 20 and 21, is located near edge 17 of platform 18. A spring 16 on platform 18 urges upright 19 into the position shown in FIG. 1. Furthermore, upright 19 is preferably made of a resilient material, whereby upright 19 will receive the main impact of the stacked sheets.

Platform 18 is vertically adjustable to keep the distance 15 between the lower face 28 and the top of the stack 46 always constant. The vertical adjustment of platform 18 may be obtained automatically through mechanical feeler or optical means (photoelectric cells not shown) located at or near platform 18.

Platform 18 recedes or is moved away from its position shown in FIG. 1 when stack 46 has reached a required height. The stacking device may be stopped during the removal of platform 18. The removal of platform 18 may be performed by hand. It may, however, be effected by electrical or fluid pressure motors, if so desired.

Sheets supplied to lower face 28 of conveyor belt 24 are retained against this face 28 approximately from point 25 towards that point where they are not yet located above platform 18.

If the front edge 33 of the sheet 32 runs below a photoelectric cell 82, interposed between the suction means 42 and 47 and receiving radiation from a lamp 83 the radiation of which pass through holes provided in the conveyor belt, a control impulse is given from the photoelectric 3 cell to control means 85 connected with a time delay device 84 (FIG. 8).

By this impulse, the control device 85 is reversed in such a way that the impulse is not further transmitted. When the rear edge of the sheet has crossed the ray, the ray again impinges on the photoelectric cell 82. This gives once more an impulse reversing the control device 35 in such a way that the impulse is given to the time delay device.

The time delay device directs the impulse, after a certain time, to an electric, mechanical or pneumatic device 90 which operates a control valve 92 to turn its valve member to another position, as illustrated in FIG. 8.

As illustrated in FIG. 8 the control valve 92 connects a vacuum pump 94, preferably connected with a vacuum accumulator, with the valved orifice units 40, 41, 4'7, 48 and 49. In another position of the valve member 92, a pressure pump 96 is connected to the orifice units 40, 41, 47, 48, 49.

An accumulator is preferably interposed to even out the pressure.

A feed distance, between successive sheets, of 20 mm. to 30 mm. was found to be sufiicient.

By supplying compressed air to the suction means 41 41, 47, 48 and 49 the sheet is thrown off downwardly. Since it still has the inherent inertia acting in the direction of its initial movement, it describes a parabolic drop ping curve until it hits the abutment 19 and slides vertically down along the latter.

A regulator 88 (FIG. 8), which is operatively connected with the conveyor belt in such a way that r.p.m. corresponds with the speed of the conveyor belt, acts on the time delay device via a control device 86 which has a face cam not shown in the drawing.

The regulator 88 can be operatively connected in well known manner to roller 22 with .the aid of drive belt 35. The cam is provided in such a way that the time delay effected by the time delay device 84 is the shorter the quicker the conveyor belt 24 moves. Thus the sheet which arrives quicker is released earlier than the slower arriving sheet. The regulator 88 can be replaced by electric control means, e.g. an electric r.p.m. or speed counter, and, instead of a face cam, may be provided with an electric transmission device.

The rays directed on cell 82 may be light rays or invisible rays, depending on the type of control device utilized, which again is determined by the sheets to be stacked, i.e., the permeability of the sheets to the different types of rays.

Conveyor belt 24 is constructed to allow application of vacuum and pressure through it to hold the sheets onto the lower belt face 28. According to one embodiment, conveyor belt 24 consists of woven wire. The lower ends of the roifice units are protected in this embodiment by resilient material, such as rubber or elastomers, in order to seal the ends of the orifices against the woven wire conveyor belt.

Conveyor belt 24 consists of an elastomeric material according to another embodiment. The elasticity of this belt provides the necessary fluid seal between conveyor belt and orifices. Elastic conveyor belts of considerable thickness provide the added advantage of protecting the surface of the sheets. Passages are formed in conveyor belts of elastomeric materials for the passage of the fluid.

A further modification of the conveyor belt is illustrated in FIG. 2. Conveyor belt 54 comprises impervious portions 55, 56, 57 and 58 and perforated portions 59, 60 and 61 spaced across the conveyor belt 54. The longitudinal edges of conveyor belt 54 are formed by the impervious portions 55, '56, also pervious and impervious portions alternate across the width of conveyor belt 54.

Additional orifice units 62 are located in line with impervious portions 55, 56, 57, 58 and 59 to act on upper face 47 of conveyor belt 54. A plurality of sets of addi tional orifice units 49 are spaced between points 59, 61

A and will assist in keeping the moving conveyor belt in a horizontal plane by urging the impervious portions 55, 56, 57, 58, 59 against the plurality of sets of horizontally located additional orifices 62 kept permanently under vacuum.

The construction of perforations 63 of the pervious portions 59, 60, 61 is shown on an enlarged scale in FIG. 3. Perforation 63 comprises a cylindrical part 65 and a downwardly and outwardly flaring lower part .64 located adjacent the lower face 47'. Vacuum and pressure will in this manner act on an increased surface area of work sheet 32.

A further modification of the conveyor belt is illustrated in FIGS. 4 and 5, and is particularly useful for sheets which are relatively thin and light in weight, such as light metal foils.

Sheets of such type have the tendency to cling to lower face 47' and the vacuum cannot be relieved fast enough to free the sheets. Furthermore, surface adhesion between the foil and lower face 47' has to be broken quickly and efficiently. The output of the stacking device would be considerably reduced if no steps are taken to overcome these disadvantages.

FIG. 4 shows a conveyor belt similar to the one shown in FIG. 2, but of increased width. The right hand edge portion of conveyor belt 51 of FIG. 4 is broken off. Further imperforated portions 58a, 58b and a further perforated portion 61a are shown in FIG. 4. The imperfo rated portions spaced from the edges of conveyor belt 51 are provided with distance means in the form of strips 52, two of which are shown in FIGS. 4 and 5. Strips 52 extend over the length of conveyor belt 51, have a width of 5 mm. to 25 mm., a thickness of 0.8 mm. to 1.5 mm. and are spaced from each other 50 mm. to mm.

Sheets supplied to the conveyor belt will tend to contact strips 52 only. The space between the strips and the other parts of lower face 47 is small enough to ensure safe transport since the small distance presents suflicient resistance to the build-up of vacuum by the orifices. The sheet will be released from lower face 47 of conveyor belt 51 quickly when the vacuum is cut off from the valved orifices. A more accurate stacking of the foils is thus obtained as would be possible with a planar lower surface 28.

The lower surface 47 may be roughened in many different ways for the transport of foils, if strips 52 are not used, to provide distance means reducing the contact area between the lower face 47' and a sheet supplied thereto.

A conveyor belt 70 (FIG. 6) has rectangular projections formed on impervious portions 67, 69 spaced on each side of a pervious portion 71. Pervious portion 71 is provided with perforations 62 passing through dimple 77 on pervious portion 71. One or more perforations can be formed in each dimple 77. Each perforation 62 is formed with a cylindrical portion 73 and a flaring portion 74 located on the lower face 47b of conveyor 71 (see FIGS. v6 and 7) provided with upper face 470.

The greater the number of projections and the closer they are spaced, the more resistance to the air they present, when a sheet is placed against lower face 47b. Projections are located in irregular fashion on a smooth or on a rough surface of the conveyor belt, if so desired.

A construction according to FIG, 7 will reduce surface adhesion to a great extent. A number of dimples may be left solid, i.e. they are devoid of perforations.

Strips 52, projections 66 and dimples 77 are made integrally with the respective conveyor belts. They can be made out of the same material and fixed to the conveyor belts if integral production is not desired. Strips 52, projection 66 and dimples 77 can also be madeout of leather and synthetic materials fixed to the conveyor belts.

Valved orifice units 40, 41, 47 48, 49 occupy a considerable space between points 25, 26 while orifices 42 occupy a small space. Orifices 42 are placed near point 25 at which the sheets are supplied to lower face 28 of the conveyor belt. Sheets 36 are securely transported and stacked in this manner. Preferably sheets are no more subject to suction by orifices 42 when they are released from lower face 28. A greater throughput and a more positive control of release of the sheets is thus obtained and the conveyor belt can travel at a considerable speed without reducing the efficiency and accuracy of the sheet stacking.

Upright 19 has to withstand considerable shock load, since sheets may impinge thereon with considerable force.

The area of upright 19 is made large enough to withstand these impact shocks. Spring 16 urging upright 19 against the sheets, assist also to reduce the shocks.

Upright 19 and guide members 20, 21 are adjustably mounted on platform 18 to serve for sheets of different sizes.

Sheet 32 will descend in a parabolic path onto platform 18. The gradient of this parabola will depend on the weight of the sheet, the time of vacuum reduction and the time of application of pressure through the valve orifices, besides other factors such as surface adhesion and the amount of pressure and vacuum.

The time delay in the release control can be adjusted in order to greatly compensate for these variations. Change in pressure and vacuum will work in the same way. The position of the valved orifices along the path the sheets travel, can also be adjusted to obtain a constant descent parabola of the sheets. Furthermore, the position of upright 19 in relation to point 26 may be adjusted to compensate for a decrease or increase of the length of the parabola of descent.

It has been found that sheets varying in length from 0.5 m. to 6 m., in width from 0.5 m. to 1.5 m. and in thickness from 0,2 mm. to 2 mm. can be quickly and efficiently stacked to present a neat stack with the edges correctly aligned.

A stack of sheets thus formed is easy to prepare for shipment and will reduce scrap and damage considerably.

Various changes and modifications may be made without departing from the spirit and scope of the present invention and it is intended that such obvious changes and modifications be embraced by the annexed claims,

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent, is:

1. A device for stacking sheets comprising, in combination, pervious conveyor means, having an upper face and a lower face and moving in one direction from a first location to a second location; feeding means adjacent said first location for supplying sheets to said lower face of said conveyor means; a plurality of orifice units operatively associated with said upper face and arranged therealong between said first and second locations; a source of vacuum; a source of pressure fluid; connecting means connecting said units to said source of vacuum, the connecting means of at least those units adjacent said second location including valve means connected to said source of pressure and selectively operable to connect the associated connecting means either only to said source of vacuum or only to said source of pressure; said units, when connected to said source of vacuum, being adapted to retain the sheets in engagement with said lower face and, when connected to said source of pressure, being adapted to force the sheets away from said lower face; control means operatively associated with said valve means, and operable, responsive to a sheet supplied to said lower face of said conveyor means reaching a selected position between said first and second locations, to operate said valve means to connect the associated units to said source of pressure whereby the sheet will then be forced from said lower face for stacking in superposed relation below and adjacent said selected position; said conveyor means comprising an endless belt, said endless belt having a plurality of perforated portions therein arranged longitudinally along said belt and a plurality of non-perforated portions extending longitudinally along said belt, said longitudinally ar- 6 ranged perforated portions being separated from each other by said longitudinally non-perforated portions, each said orifice unit being arranged on the upper face of the conveyor means belt so as to be adjacent a longitudinally extending perforated portion of said belt; and a plurality of additional orifice units permanently connected with said source of vacuum, each said additional orifice unit being arranged on the upper face of said endless belt adjacent a non-perforated longitudinally extending portion thereof for maintaining suction on said belt to prevent said endless belt of said conveyor means for moving laterally during the motion from said first location to said second location.

2. A device for stacking sheets comprising, in combination, pervious conveyor means, having an upper face and a lower face and moving in one direction from a first location to a second location; feeding means adjacent said first location for supplying sheets to said lower face of said conveyor means; a plurality of orifice units operatively associated with said upper face and arranged therealong between said first and second location; a source of vacuum; a source of pressure fluid; connecting means connecting said units to said source of vacuum, the connecting means of at least those units adjacent said second location including valve means connected to said source of pressure and selectively operable to connect the associated connecting means either only to said source of vacuum or only to said source of pressure; said units, when connected to said source of vacuum, being adapted to retain the sheets in engagement with said lower face, and, when connected to said source of pressure, being adapted to force the sheets away from said lower face; and control means operatively associated with said valve means, and operable in response to a sheet supplied to said lower face of said conveyor means reaching a selected position between said first and second locations to operate said valve means to connect the associated units to said source of pressure, whereby the sheet will then be forced from said lower face for stacking in superposed relation below and adjacent said selected portion, said control means including a detector cooperable with the edge of a sheet on said lower face to provide a signal to a control device included in said control means, said control means including a time delay device and a regulator, said regulator being operable in accordance with the speed of operation of said conveyor means to adjust the delay time of said time delay means in inverse ratio to the speed of said conveyor means.

3. A device for stacking sheets comprising, in combination, pervious conveyor means, having an upper face and a lower face and moving in one direction from a first location to a second location; feeding means adjacent said first location for supplying sheets to said lower face of said conveyor means; a plurality of orifice units operatively associated with said upper face and arranged therealong between said first and second location; a source of vacuum; a source of pressure fluid; connecting means connecting said units to said source of vacuum, the connecting means of at least those units adjacent said second location including valve means connected to said source of pressure and selectively operable to connect the associated connecting means either only to said source of vacuum or only to said source of pressure; said units, when connected to said source of vacuum, being adapted to retain the sheets in engagement with said lower face, and, when connected to said source of pressure, being adapted to force the sheets away from said lower face; and control means operatively associated with said valve means, and operable responsive to a sheet supplied to said lower face of said conveyor means reaching a selected position between said first and second locations to operate said valve means to connect the associated units to said source of pressure, whereby the sheet will then be forced from said lower face for stacking in superposed relation below and adjacent said selected portion, said control means including a detector cooperable with the edge of a sheet on said lower face to provide a signal to a control device including a time delay device and a regulator, said regulator being operable in accordance with the speed of operation of said conveyor means to adjust the delay time of said time delay means in inverse ratio to the speed of said conveyor means, said control means being operable in response to the trailing edge of a sheet on said lower face passing said selected position to operate said valve means to connect the associated units to said source of pressure, said detector device being further connected to the operating means for said valve means to a timing relay operable to effect actuation of the operating means for said valve means a predetermined time after said trailing edge has passed said selected position.

References Cited in the file of this patent UNITED STATES PATENTS Fischer May 30, Jones June 28, Huflrnan Jan. 18, Nebolsine Oct. 25, Long July 14, Pfister Nov. 5, Perry et a1 Nov. 19, Pomper July 21 Makrides Sept. 22, 

1. A DEVICE FOR STACKING SHEETS COMPRISING, IN COMBINATION, PREVIOUS CONVEYOR MEANS, HAVING AN UPPER FACE AND A LOWER FACE AND MOVING IN ONE DIRECTION FROM A FIRST LOCATION TO A SECOND LOCATION; FEEDING MEANS ADJACENT SAID FIRST LOCATION FOR SUPPLYING SHEETS TO SAID LOWER FACE OF SAID CONVEYOR MEANS; A PLURALITY OF ORIFICE UNITS OPERATIVELY ASSOCIATED WITH SAID UPPER FACE AND ARRANGED THEREALONG BETWEEN SAID FIRST AND SECOND LOCATIONS; A SOURCE OF VACUUM; A SOURCE OF PRESSURE FLUID; CONNECTING MEANS CONNECTING SAID UNITS TO SAID SOURCE OF VACUUM, THE CONNECTING MEANS OF AT LEAST THOSE UNITS ADJACENT SAID SECOND LOCATION INCLUDING VALVE MEANS CONNECTED TO SAID SOURCE OF PRESSURE AND SELECTIVELY OPERABLE TO CONNECT THE ASSOCIATED CONNECTING MEANS EITHER ONLY TO SAID SOURCE OF VACUUM OR ONLY TO SAID SOURCE OF PRESSURE; SAID UNITS, WHEN CONNECTED TO SAID SOURCE OF VACUUM, BEING ADAPTED TO RETAIN THE SHEETS IN ENGAGEMENT WITH SAID LOWER FACE AND, WHEN CONNECTED TO SAID SOURCE OF PRESSURE, BEING ADAPTED TO FORCE THE SHEETS AWAY FROM SAID LOWER FACE; CONTROL MEANS OPERATIVELY ASSOCIATED WITH SAID VALVE MEANS, AND OPERABLE, RESPONSIVE TO A SHEET SUPPLIED TO SAID LOWER FACE OF SAID CONVEYOR MEANS REACHING A SELECTED POSITION BETWEEN SAID FIRST AND SECOND LOCATIONS, TO OPERATE SAID VALVE MEANS TO CONNECT THE ASSOCIATED UNITS TO SAID SOURCE OF PRESSURE WHEREBY THE SHEET WILL THEN BE FORCED FROM SAID LOWER FACE FOR STACKING IN SUPERPOSED RELATION BELOW AND ADJACENT SAID SELECTED POSITION; SAID CONVEYOR MEANS COMPRISING AN ENDLESS BELT, SAID ENDLESS BELT HAVING A PLURALITY OF PERFORATED PORTIONS THEREIN ARRANGED LONGITUDINALLY ALONG SAID BELT AND A PLURALITY OF NON-PERFORATED PORTIONS EXTENDING LONGITUDINALLY ALONG SAID BELT, SAID LONGITUDINALLY ARRANGED PERFORATED PORTIONS BEING SEPARATED FROM EACH OTHER BY SAID LONGITUDINALLY NON-PERFORATED PORTIONS, EACH SAID ORIFICE UNIT BEING ARRANGED ON THE UPPER FACE OF THE CONVEYOR MEANS BELT SO AS TO BE ADJACENT A LONGITUDINALLY EXTENDING PERFORATED PORTION OF SAID BELT; AND A PLURALITY OF ADDITIONAL ORIFICE UNITS PERMANENTLY CONNECTED WITH SAID SOURCE OF VACUUM, EACH SAID ADDITIONAL ORIFICE UNIT BEING ARRANGED ON THE UPPER FACE OF SAID ENDLESS BELT ADJACENT A NON-PERFORATED LONGITUDINALLY EXTENDING PORTION THEREOF FOR MAINTAINING SUCTION ON SAID BELT TO PREVENT SAID ENDLESS BELT OF SAID CONVEYOR MEANS FOR MOVING LATERALLY DURING THE MOTION FROM SAID FIRST LOCATION TO SAID SECOND LOCATION. 